The present invention relates to a system for measuring contact pressure between a tongue and a palate during speech production (in this description, this system is referred to as a xe2x80x9ctongue pressure measuring systemxe2x80x9d), and the system is applicable for the study of phonetic science, rehabilitation exercise for a person having articulation impediments, and so forth.
It is known that contact of a tongue with a palate is an important factor for pronouncing a consonant. Thus, an observation of contact condition of the tongue is very important for studying phonetic science and rehabilitation exercise for a person having articulation impediments.
Since the contact condition between the tongue and the palate at the time of utterance or during speech production cannot be observed directly, the following techniques (1) to (4) have been used. However, they have a variety of problems.
(1) Technique Using X-ray
This technique only enables the observation of an oral cavity from a single direction and cannot provide detailed information. This also has a problem of X-ray exposure.
(2) Technique Using MRI
This technique enables a three-dimensional observation of an oral cavity without the problem of X-ray exposure. However, because it takes time to obtain images, this technique is not suitable for imaging the contact conditions during production of most consonants.
(3) Technique Using Electro-palatography
In this technique, many electrodes are arranged on the palate of a speaker, and, based on the contact/noncontact information of the tongue with the electrodes, the contacting area is observed. However, it is impossible to observe a distribution or a variation of contact pressures.
(4) Technique Using a Strain Gauge type Pressure Sensor
This has been developed to overcome the drawbacks of the above techniques (1) to (3). However, in this technique, the sensor per se has a large size and, since the sensor also responds to a variation of pressure in an oral cavity, it it difficult to observe the accurate tongue-palate contact pressure per se.
Consequently, in the field utilizing these kinds of techniques, there has been a desired demand to develop a tongue pressure measuring system which can provide an accurate, real-time measurement of the tongue-palate contact pressure during speech production without disturbing natural utterance.
It is hence an object of the present invention to provide a tongue pressure measuring system which can provide an accurate, real-time measurement of the tongue-palate contact pressure during speech production without disturbing natural utterance.
The tongue pressure measuring system according to the present invention includes a thin palate floor plate in a shape matching with the shape of a user""s palate, thin pressure sensor sheets having a plurality of pressure sensing cells secured to a lower surface of the palate floor plate, an attaching means for attaching the palate floor plate to a proper position on the palate and cables for transmitting information from the respective pressure sensing cells of the pressure sensor sheets to an apparatus outside of an oral cavity. The cables are led out of the. oral cavity extending around.the rearmost tooth and passing along the vestibule of the oral cavity with the palate floor plate being attached on the palate. Each of the pressure sensor sheets includes two resin backings structured in one body and contains air therein hermetically along an outline thereof. The backings include a plurality of electrodes covered with pressure-sensitive ink layers on one side of each backing, and the electrodes are opposed to each other through the pressure-sensitive ink layers. Portions corresponding to the opposing electrodes and the pressure-sensing ink layers form the pressure sensing cells.
The tongue pressure measuring system according to the present invention includes a thin palate floor plate in a shape matching with the shape of a user""s palate, thin pressure sensor sheets having a plurality of pressure sensing cells secured to a lower surface of the palate floor plate, an attaching means for attaching the palate floor plate to a proper position on the palate and cables for transmitting information from the respective pressure sensing cells of the pressure sensor sheets to an apparatus outside an oral cavity. The cable is led out of the oral cavity extending around the rearmost tooth and passing along the vestibule of the oral cavity with the palate floor plate being attached on the palate. Each of the pressure sensor sheets includes two resin backings structured in one body and contains air therein hermetically along an outline thereof. The backings have a plurality of electrodes on one side of each backing and the electrodes oppose to each other. The electrodes on one of the backings are provided with a pressure-sensitive ink layer. Portions corresponding to the opposing electrodes and the pressure-sensing ink layer form the pressure sensing cells.
In another embodiment of the tongue pressure measuring of the present invention, air is sealed within each of the pressure sensor sheets so as to form a gap between opposing pressure sensitive ink layers which coat the opposing electrodes.
In another embodiment of the tongue pressure measuring system of the present invention include air sealed within each of the pressure sensor sheets so as to form a gap between the electrodes and the pressure sensitive ink layer coated over the electrodes opposing thereto.
In another embodiment of the tongue pressure measuring system of the present invention air is allowed to flow around and back and forth among the pressure sensing cells.
In another embodiment of the tongue pressure measuring system of the present invention, each of the pressure sensor sheets has a least one air storage portion in communication with portion of the pressure sensing cells.
In a further embodiment of the tongue pressure measuring system of the present invention, the cables are coated with a non-conductive member.
The function of the tongue pressure measuring system of the present invention stated above will be described in detail in the following section of the detailed description of the preferred embodiments.